httpboot: fix the infinite loop
httpboot: fix the infinite loop

We should get out of the loop once the uri node is not the last node in
the device path.

Signed-off-by: Gary Lin <a057d4b27e9e9055b973f54b519db54c22ed5ee8@suse.com>

rhinstaller/shim,rhinstaller/shim,rhinstaller/shim